Beware Familiar Spirits by John Mulholland.

John Mulholland (9 June 1898 in Chicago, Illinois – 25 February 1970 in New York City) was an American magician, author, publisher and intelligence agent. Mulholland learned the art of magic as a teenager with John William Sargent, President of the Society of American Magicians. Mulholland was a professional magician for two decades, working in small companies and large stage shows. He ran one of the first magic workshops and was from 1930 the editor of the magical trade magazine The Sphinx.

He published many books on magic and its history. Mulholland was a close friend of Harry Houdini . Mulholland asserted that “Houdini once told me that he considered no man to be a magician until he was able skillfully to perform the cups and balls.”

Mulholland had criticized the claims of parapsychology and exposed the tricks of fraudulent spiritualist mediums. This book Beware Familiar Spirits (1938) revealed many of these tricks. Millions believe in spirits. This amazing and factual account of ghostly beings, their work, and their masters, tells why. It is the product of long study and careful investigation by the author, a close student of Spiritism for many years.